/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.nexmark.queries;



import com.bff.gaia.unified.sdk.nexmark.model.Event;

import com.bff.gaia.unified.sdk.nexmark.model.KnownSize;

import com.bff.gaia.unified.sdk.transforms.PTransform;

import com.bff.gaia.unified.sdk.values.KV;

import com.bff.gaia.unified.sdk.values.PCollection;



import javax.annotation.Nullable;



/**

 * Base class for 'NEXMark' query transforms.

 *

 * <p>A query transform maps an event stream to some known size element stream.

 *

 * <p>A query transform may request a faked side input to join with ids.

 */

public abstract class NexmarkQueryTransform<T extends KnownSize>

    extends PTransform<PCollection<Event>, PCollection<T>> {



  private transient PCollection<KV<Long, String>> sideInput = null;



  protected NexmarkQueryTransform(String name) {

    super(name);

  }



  /** Whether this query expects a side input to be populated. Defaults to {@code false}. */

  public boolean needsSideInput() {

    return false;

  }



  /**

   * Set the side input for the query.

   *

   * <p>Note that due to the nature of side inputs, this instance of the query is now fixed and can

   * only be safely applied in the pipeline where the side input was created.

   */

  public void setSideInput(PCollection<KV<Long, String>> sideInput) {

    this.sideInput = sideInput;

  }



  /** Get the side input, if any. */

  public @Nullable

  PCollection<KV<Long, String>> getSideInput() {

    return sideInput;

  }

}